Setting Up the RHEV Virtual Infrastructure - Getting Started with Red Hat Enterprise Virtualization - page 55

Required networks must be applied to all hosts in a cluster for the cluster and net-
work to be operational. When a required network becomes nonoperational, the
virtual machines running on the network are fenced and migrated to another host.
This is beneficial if you have machines running on mission critical workloads.
When a non-required network becomes nonoperational, the virtual machines run-
ning on the network are not migrated to another host. This prevents unnecessary
I/O overload caused by mass migrations.
Note
Optional networks are the logical networks that have not been explicitly declared
in the same way as required networks are. Optional networks can be implemented
on only the hosts that use them. The presence or absence of these networks does
not affect the operational status of a host. Optionally, you can select the logical
network used for any of the three functionalities: VM, Display, and Migration
Network. Select VM Traffic so that we can use this logical network for all our
virtual machine network traffic.
6. Select the option relevant to your requirements and click on OK .
Tip
Note that you can't edit the RHEV-M logical network. Multiple Virtual LANs
( VLANs ) can be added to a single or bonded network interface to separate traffic
based on VLAN.
7. Navigate to the Host tab. Select the hosts and click on the Network Interface
tab.
8. Click on Set up Host Networks .
9. Drag your newly created logical network from the left-hand side under the
Assigned Logical Networks area next to the physical network. In our case, we
dragged vmdata01 and tied it to the physical interface eth2 . Check the Save net-
work configuration checkbox and click on OK to finalize the network setup.
10. If everything is configured properly, you will see your new logical network at-
tached to the physical NIC, and the interface status changes from the Down state
to the Up state under the Network Interfaces tab of the hosts, as shown in the
following screenshot: